New 470 Mercruiser Owner

[pcmpete]

Just picked up a nice FREE 1978 18' Reinall ski boat. It was free because it has Mercruiser 470 with a blown head gasket, everything else about the boat is near perfect. I own volvo pentas, but this is my first mercruiser.....Questions:

Can the head gasket be replaced without pulling the engine?

What is the rated HP of this motor?

Is this motor based on an Auto engine, if so which one?

What else to check for on a Mercruiser?

The only numbers I can find are the following.

Engine: 4874676

Outdrive: 77124

i know people will ask for photos, I will post them as soon as....


Thanks

 

[Don S]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

The 470 is not an automotive engine. It was designed and built by Mercruiser. PS: They stopped building them in 89 and parts are getting hard to find.
Since you have a 78, that means you have one of the early/original engines. Probably with a 3" heat exchanger, which was a big problem and caused overheates, which in the 470 (due to open deck design of the aluminum block) also cause head gaskets to blow. The raw water pump in the drive also needs to be changed at least yearly to prevent possible overheats. Then you have the charging system that is designed like an outboard with stator and a pulley with magnets mounted to the front of the crankshaft. The parts are expensive and some are NLA. The regulators (water cooled) are around $375 from aftermarket sources. OEM's are expensive. Then there is the cam seal that likes to leak antifreeze into the engine oil. Not Good.
Along with the engine, you are going to need to pull the drive, look for water in the bellows, probably change the bellows, and who knows what else.
Looks don't mean everyting with IO's, especially the 470. I can see you spending a lot of money getting the boat ready for the water again.
Head up to the Adults Only sticky at the top of this forum and download service manual #3 for the engine and 4 for the outdrive. You are going to need them.
Might want to do some other reading up there while you are at it.

 

[pcmpete]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

thanks for your quick reply. Worse case... I will be posting alot on craigslist

 

[pcmpete]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

Don, link to outdrive manual #4 is not valid

 

[Don S]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

Don, link to outdrive manual #4 is not valid

Yeah, people haven't kept up with their 4shared sites, if you don't log in at least every 30 days, they are deleted. I haven't checked lately to see what is good and what isn't anymore.

 

[pcmpete]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

The 470 is not an automotive engine.

Is the Head the same as a Ford Big Block Head?

 

[Don S]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

Yes, the head is from a 460 Ford.
PS: Working on getting a working link for the #4 manual.

 

[pcmpete]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

Yes, the head is from a 460 Ford.
PS: Working on getting a working link for the #4 manual.

Again, thank you for your time.

 

[stonyloam]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

Can the head gasket be replaced without pulling the engine?

What is the rated HP of this motor?

Is this motor based on an Auto engine, if so which one?

What else to check for on a Mercruiser?

The only numbers I can find are the following.

Engine: 4874676

Outdrive: 77124

i know people will ask for photos, I will post them as soon as....


Thanks

Ok I'll try to answer your questions as best I can. In order

Head gasket: Yes (well if you have the room to get at it), not too bad a job. I would suggest that you get a valve job done while the head is off. Follow the manual instructions EXACTLY, and use OEM Mercruiser head gasket.

HP about 165 (2 bbl)

NO

Leaky front waterpump cam seal. As Don Says. Check out this link http://www.sterndrives.com/470information/470coolantleakrepair.html Job is not too bad, if you can get the balancer off. When you get it started, if the charging system does not work get the alternator kit from Breezeworks. Yes a 4" heat exchanger is a must (about $400 new).

for the outdrive listen to what Don says.

A lot of guys really don't like this engine, but if you can get it running it is not so bad (and they never freeze). Good luck

 

[pcmpete]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

Thanks guys for the input, as long as know what the weak points of this motor/drive combo are so I can form a plan of attack.

I don't mind pulling the engine, but would like to avoid it if possible when changing the head gasket and cam seals. My concern is the price of the 4" heat exchanger and the alternator conversion.
So is it possible:

1. to fit another heat exchanger from another mercruiser engine (secondhand), if so which one should I be looking for?

2. to fit another alternator and brackets from another mercruiser engine (secondhand), if so which one should i be looking for.

As pointed out, this two items are pricey.


and finally, what would be a good replacement engine for the 470 if I came across one during my travels that didn't involve changing ratios, motor mounts etc.....


Thanks again

P.s. this boat may become a birthday gift to my son for his 21st, so i don't mind spending some time and money on it

 

[Don S]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

1. to fit another heat exchanger from another mercruiser engine (secondhand), if so which one should I be looking for?

There really isn't one. You also have to consider where it will be located, how it's mounted and the hoses to fit.

2. to fit another alternator and brackets from another mercruiser engine (secondhand), if so which one should i be looking for.

Again, there isn't one.

and finally, what would be a good replacement engine for the 470 if I came across one during my travels that didn't involve changing ratios, motor mounts etc.....

Probably tired of hearing this already, but there isn't one.

That is one of the big problems with that engine. V6 HP, 4 cylinder space and front motor mount. For a V6 or even an inline 6, the motor mounts will change, along with the exhaust tube/Y on the transom shield.

Everything on that engine and setup is one of a kind.

 

[stonyloam]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

3.7 (470) heat exchangers come up on e-bay all the time. Matter of fact there is a pretty good looking one there now for $200. do a search for "mercruiser heat exchanger". As for the alternator, IF the charging system works when you get it running, don't worry about it till it stops working. Then replace it with the alternator. The problem is not that they don't work well (mine is 23 years old and still works OK), the problem is if they stop working it is REALLY expensive to fix them. The water cooled voltage regulator costs more than the alternator kit. Welcome to my world.

 

[HT32BSX115]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

Howdy,

what would be a good replacement engine for the 470 if I came across one during my travels that didn't involve changing ratios, motor mounts etc.....

I'll second the "there isn't one"........ but you'll probably still be better off parting out that complete engine and finding a used V-6, mounts etc.... because you won't have to "re-invent the wheel" trying to make that thing work.....

Most all boats had engine compartments that were designed to accept a variety of optional engine sizes....so switching to something else wouldn't be all that hard and you and your son can have a lot more fun doing the installation and use the boat instead of fighting with an obsolete engine with unique problems......


Good luck,


Rick

 

[NetMatrix]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

I have a MerCruiser 470 myself and after I did the pricing depending on what you will have to fix in the future on that motor cheaper to go with a different motor. Very powerful in the water, but honestly not worth the future costs of repairs.

 

[q5ka]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

If you think that the price of these fixes/changes needed to get your 470 going is too much, I would tell you to walk away from this engine. If you notice in my signature, I have the newer style 470 and you are dealing with a motor that has limited new parts (you can mostly find them but they are not produced by Mercruiser and most aftermarket parts are not mass produced so they just cost more). Don is not trying to call doom in your general direction but telling you what would be the bare minimum you need to deal with. You could tackle it in stages but you have to think if the boat or engine is worth the cost. Remember that it is 31+ years old. These motors have a lot of torque and get very acceptable fuel usage. They wont beat a v-8 in power but they will compete with v-6 in power while sip fuel like the i-4 it is. Open your motor up and check the head. Figure out the cost of fixing the overheat and then decide if you want to deal with it. If so, then check EBay and see what you will find.

 

[artificialreef]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

Wow, im impressed. Not many opinions saying run from that even though its free! Since he got it free is there an aluminum head he can get to get around the contradicting metals.

 

[pcmpete]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

After searching ebay, online marine stores and watching a few youtube videos about the 470, i think I will stick with it. The general vote is when it is running it runs good and strong. Heck, any engine can break down and need repaired, plus this will bring my boat count up to 3, if the 470 breaks down I can still get out on the water.
Thanks for all your input guys.
I am sure I will have more questions as I dig into the 470.
Just to be sure, can anyone confirm what drive came with the 470?

 

[stonyloam]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

I read your other thread and if you can build and fly a RC helicopter, this should be easy. I looked into replacing my 470 with a V6, but was going to be WAY too much time, work and money. Replacing the head gasket (in boat) by myself took about 7 hours total (I am no master mechanic). The gaskets ran about $100, and I had a valve job (new exhaust seats) done. Total cost was about $500. To do the cam seals, about $150 for parts. 4 or 5 hours, IF you can get the harmonic balancer off in the boat. If the seals have been replaced sometime in the past, they may not leak, but will leak sometime in the future. Make sure that the little weep hole on the starboard lower side of the circulating pump on the front of the engine is not plugged. No such thing as a free boat,but you might just get lucky .

 

[achris]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

After searching ebay, online marine stores and watching a few youtube videos about the 470, i think I will stick with it. The general vote is when it is running it runs good and strong. Heck, any engine can break down and need repaired, plus this will bring my boat count up to 3, if the 470 breaks down I can still get out on the water.
Thanks for all your input guys.
I am sure I will have more questions as I dig into the 470.
Just to be sure, can anyone confirm what drive came with the 470?

The drive on that engine package is known as an MC-1, or Mercruiser 1 drive. That drive is the same as all the drives of that era. Just the ratios where different according to which engine they were bolted up to. The ratio for the '470' was 1.84:1.

The name '470' comes from 4 cylinder, 170 hp. The crank, head, and pistons are from a Ford 460 engine, and that is where the similarity ends I'm afraid.

As much as I like them I have to agree with all the comments voiced thus far. They are 'nice' engines for what they are, easy to work on, but have their idiosyncrasies, most of which cost big $$$ to fix.

Good luck with it, I'm sure we'll hear from you again.

Chris......

 

[pcmpete]

Re: New Mercruiser Owner

Re: New Mercruiser Owner

I read your other thread and if you can build and fly a RC helicopter, this should be easy.

Yeah, the helicopters building and flying is fun. Crashing and re-building not as much fun, but STILL part of the hobby. Just like owning an old boat engine/outdrive. The hobby has has given me great skills and education over the past 20 years that I have been flying them. Boats are just bigger and need bigger tools. :redface:
But I love the feeling of building something and making it work the way it should, it is like a drug sometimes. Now I am just rambling.......

No such thing as a free boat,but you might just get lucky.

Well, I am 100% Irish, moved from Ireland to the states about 3 years ago